Question

Please help me
Today is my exam...
Multiply x²+4y²+z2+2xy+xz-2yz by -z+x-2y

Answer 1

$({x}^{2} + {4y}^{2} + {z}^{2} + 2xy + xz - 2yz) \times ( - z + x - 2y) \\ \\ - z( {x}^{2} + {4y}^{2} + {z}^{2} + 2xy + xz - 2yz) + x ({x}^{2} + {4y}^{2} + {z}^{2} + 2xy + xz - 2yz) - 2y ({x}^{2} + {4y}^{2} + {z}^{2} + 2xy + xz - 2yz) \\ \\ { - zx}^{2} - {4zy}^{2} - {z}^{3} + 2xyz - {xz}^{2} + {2yz}^{2} + {x}^{3} + {4y}^{2}x + {z}^{2}x + {2x}^{2}y + {x}^{2}z - 2xyz - {2yx}^{2} - {8y}^{3} - {2yz}^{2} - {4xy}^{2} - 2xyz + {4y}^{2}z \\ \\ {x}^{3} + {12xy}^{2} - 6xyz - {32y}^{3} - {12y}^{2}z - {z}^{3}$